Adding USB Ports to the Raspberry Pi Zero
My one frustration with the Raspberry Pi Zero is the fact that it doesn’t have “real” USB ports. While I understand the necessity the idea of having trailing dongles hanging off the board always irritates me every so slightly.
However the discovery that the USB bus could be accessed from exposed test pads on the underside of the board has more or less fixed this problem for me.
The first board I came across to make use of this feature of the Zero was the Hubpixed, it uses four mechanical spring connectors to connect to the test points available on the bottom side of the board, providing four normal sized USB ports.
Providing additional USB ports this way leaves the GPIO headers entirely free, which means that a Raspberry Pi Zero pHAT — usually referred to as a “bonnet”—can be attached to the open header block in the normal way.
The arrival of these pogo-pin attached daughter boards adds a lot of flexibility to the Raspberry Pi Zero ecosystem, and there has been a number of boards that made use of the exposed pads to add missing functionality to the Pi Zero. These include a number that look a lot like the Hubpixed, for instance the Zero4U or the Waveshare USB HAT, with the creator of the Hubpixed even recently returning to Kickstarter with the HubSerialixed a combined USB Hub and UART daughter board.
However my favourite of these pad-connected boards has to be the Zero Stem.
The Zero Stem is a low-profile shim the means your Raspberry Pi can be plugged directly into a computer or USB hub without any additional cables or power supplies. Unlike the Hubpixed or Zero4U the ZeroSteam is soldered to the back of your Raspberry Pi Zero so it’s a permanent addition to the board, and probably not something you want to attempt if you’ve just started out with soldering. But once you’ve enabled USB device mode in software, the board is my “go to” for setting up the Raspberry Pi Zero (and Zero W) without access to a USB keyboard, mouse, or HDMI monitor.
So if your pain point with the Raspberry Pi Zero (or Zero W) is the lack of USB ports, it’s a pain point that can be easily solved, and while I haven’t seen many of them yet, I’m looking forward to seeing more USB ‘devices’ (rather than just more USB ports) built as daughter boards attached to the same USB test pads.